The widespread use of atomic clocks, computer networks, satellite positioning receivers and devices that incorporate satellite receivers has made synchronizing time a nearly fully automated process. However, one aspect of time setting that still requires manual intervention is setting the correct time zone based on participation in daylight savings time (DST) or other deviation from the actual time zone associated with a region.
In accordance with the standard or universal time zone map as shown, for example, in FIG. 3, to be described in greater detail hereinafter, the globe can be divided into zones of about 15 degrees that correspond to one hour intervals from a reference zone known as Greenwich Mean Time (GMT). While the mathematical determination of a time zone for a given location is relatively simple, geopolitics influences whether or not a country or a region adopts the mathematical time zone as its accepted time zone. China, for example, spans many actual time zones but uses a single time zone throughout the country based on political convention. While the mathematical time zone boundaries generally follow every 15 degrees of longitude, in practice, the lines are moved to follow geopolitical boundaries. Since the boundaries, as well as their corresponding DST rules are subject to change, and since changes are not coordinated and adopted in a uniform fashion by a global authority, providing accurate automated time zone setting becomes a difficult task. Further complicating accurate time zone setting is that some regions of the world participate in Daylight Savings Time (DST) while others do not. Still further, different countries observe DST during different times of the year and according to different start times and end times.
A conventional approach is to provide a capability to manually set the time zone and presumes that time zone settings will not change often. The Windows® Operating System, for example, allows the user to select the time zone by clicking on a region of a map and checking if DST is observed or not. In other systems, such as alarm clocks, a mechanical switch can be provided to select the time zone. In still other systems, such as SPS navigation systems, the current time zone is also manually set. Such approaches can be inconvenient where, for example, a user interface is not provided, or where equipment having a common software load or initial configuration is shipped to many different parts of the world, or may be used across many time zones. It would be desirable therefore in the art for a capability to provide an accurate time zone.